feat: implement dashboard widgets functionality

Backend:
- Add dashboard API router with widget endpoints
- Create dashboard schemas for widget data
- Add dashboard tests

Frontend:
- Enhance Dashboard page with widget components
- Add dashboard service for API calls
- Create reusable dashboard components

OpenSpec:
- Archive add-dashboard-widgets change
- Add dashboard capability specs

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

openspec/changes/archive/2026-01-07-add-dashboard-widgets/tasks.md

@@ -0,0 +1,59 @@
+# Implementation Tasks
+
+## Phase 1: Backend API
+
+### Task 1.1: Create Dashboard Schema
+- [ ] Create `backend/app/schemas/dashboard.py` with response models
+  - `TaskStatistics`: assigned_count, due_this_week, overdue_count, completion_rate
+  - `DashboardResponse`: task_stats, workload_summary, health_summary
+- **Validation**: Schema imports without errors
+
+### Task 1.2: Create Dashboard Router
+- [ ] Create `backend/app/api/dashboard/router.py`
+- [ ] Implement `GET /api/dashboard` endpoint
+  - Query tasks assigned to current user
+  - Reuse workload service for current week summary
+  - Reuse health service for project summary
+- [ ] Register router in `backend/app/main.py`
+- **Validation**: `curl -H "Authorization: Bearer $TOKEN" http://localhost:8000/api/dashboard` returns valid JSON
+
+## Phase 2: Frontend Implementation
+
+### Task 2.1: Create Dashboard Service
+- [ ] Create `frontend/src/services/dashboard.ts`
+- [ ] Define TypeScript interfaces matching backend schema
+- [ ] Implement `getDashboard()` API function
+- **Validation**: TypeScript compiles without errors
+
+### Task 2.2: Implement Dashboard Components
+- [ ] Create `StatisticsCard` component for task stats
+- [ ] Create `WorkloadWidget` component (reuse styles from WorkloadPage)
+- [ ] Create `HealthSummaryWidget` component
+- [ ] Create `QuickActions` component with navigation links
+- **Validation**: Components render without console errors
+
+### Task 2.3: Integrate Dashboard Page
+- [ ] Replace placeholder content in `Dashboard.tsx`
+- [ ] Add loading state with Skeleton components
+- [ ] Add error handling with retry
+- [ ] Style components to match existing UI
+- **Validation**: Dashboard displays data correctly after login
+
+## Phase 3: Testing & Polish
+
+### Task 3.1: Add Backend Tests
+- [ ] Create `backend/tests/test_dashboard.py`
+- [ ] Test endpoint returns correct structure
+- [ ] Test data aggregation logic
+- **Validation**: `pytest tests/test_dashboard.py -v` passes
+
+### Task 3.2: Visual Polish
+- [ ] Ensure responsive layout for mobile
+- [ ] Match color scheme with existing pages
+- [ ] Add subtle animations for loading states
+- **Validation**: Manual visual review on different screen sizes
+
+## Dependencies
+
+- Tasks 2.x depend on Task 1.2 completion
+- Task 3.1 can run in parallel with Phase 2